The present invention relates to a refrigerator, and more particularly to a refrigerator which contains a heat exchanger which mates an outer surface of a connection refrigerant tube between a food compartment evaporator and a freezer compartment evaporator with an outer surface of an intercooler refrigerant tube extended from a condenser.
A refrigerator including an intercooler refrigerating system which exchanges heat between a refrigerant tube extended from one region of a condenser with that of a refrigerant tube in an evaporator is known. With this refrigerator, subcooling of the condensed refrigerant and increasing of the temperature of the refrigerant flowing back to a compressor is achieved.
FIG. 5 shows a configuration of a refrigerator having a conventional intercooler refrigerating system. As depicted, the conventional refrigerating system includes a compressor 51 installed on the lower rear side of the main body of the refrigerator, a condenser 53 formed of a condenser tube 54 disposed over the whole region of the main body, a capillary tube 55 for expanding the refrigerant, a food compartment evaporator 58 for evaporating the refrigerant and cooling a food compartment, and a freezer compartment evaporator 57 for evaporating the refrigerant and cooling a freezer compartment.
The freezer compartment evaporator 57 and the food compartment evaporator 58 are connected in series to each other so that the refrigerant flows from the freezer compartment evaporator 57 to the food compartment evaporator 58. As shown in FIG. 6, the food compartment evaporator 58 is comprised of a plurality of heat transfer fins 63 which are disposed with spaces therebetween of a certain distance and a refrigerant tube which serpentines through the heat transfer fins 63.
The refrigerant tube of the food compartment evaporator 58 is formed of an inner tube 60 having a predetermined small diameter and an outer diameter tube 62 next to the outer surface of the inner tube 60, as particularly shown in FIG. 7. The inlet or entrance of a connection refrigerant tube 59 is connected to the freezer compartment evaporator 57 and the outlet or exit of the connection refrigerant tube 59 is connected to the inlet of the outer tube 62 of the food compartment. The condenser tube 54 extended from the condenser 53 is soldered at the entrance of the inner tube 60 of the food compartment. The connecting tube 65 is connected to the outlet of the outer tube 62 and to the inlet of compressor 51. Finally, the inlet of the capillary tube 55 is connected to the outlet inner tube 60.
Thus, the refrigerant tube in the food compartment evaporator 58 is comprised of the outer tube 62 and the inner tube 60 which are extruded integrally. The refrigerant supplied from the freezer compartment evaporator 57 flows through the outer tube 62 and the refrigerant supplied from the condenser 53 flows through the inner tube 60. Thus, the refrigerant flowing through the inner tube 60 flows in the opposite direction to that flowing through the outer tube 62.
When the refrigerating system operates, the refrigerant compressed in the compressor 51 flows into the condenser 53 and is condensed while flowing through the condenser tube 54. The refrigerant flowing through the condenser tube 54 flows into the inner tube 60 of the refrigerant tube in the food compartment evaporator 58. The refrigerant flowing through the inner tube 60 is in heat exchange with the refrigerant flowing through the outer tube 62 thereof. Thus, the refrigerant flowing through the inner tube 60 is subcooled by the refrigerant in outer tube 62 before being discharged to the refrigerant tube connected to the capillary tube 55. Then, the refrigerant is expanded through the capillary tube 55. The expanded refrigerant flows into the freezer compartment evaporator 57. Low temperature refrigerant flowing into the freezer compartment evaporator 57 is in heat exchange with the freezer compartment, thereby increasing the temperature of the refrigerant. Then, the refrigerant flows into the outer tube 62 in the food compartment evaporator 58. The refrigerant flowing through the outer tube 62 receives heat from the refrigerant flowing through the inner tube 60, thereby increasing the temperature of the refrigerant in outer tube 62. Then, the refrigerant in outer tube 62 flows back to the compressor 51 through the compressor tube 65.
In the above refrigerating system, heat exchange between the refrigerant flowing through the inner tube 60 in the refrigerant tube for the food compartment evaporator 58 and the refrigerant flowing through the outer tube 62 therein is achieved. It will be appreciated that the temperature of the refrigerant flowing through the inner tube 60 decreases; as a result, a condensation efficiency of the refrigerant increases. In addition, the refrigerant flowing through the outer tube 62 flows into the compressor 51 after its temperature increases, thus preventing damage to the compressor 51.
Meanwhile, the condenser tube 54 is connected to the inner tube 60 of the food compartment evaporator 58, and the connection refrigerant tube 59 and the compressor tube 65 are connected to the outer tube 62 thereof. The inner tube 60 and the outer tube 62 have smaller diameters than that of the condenser tube 54, the connection refrigerant tube 59 and the compressor tube 65. Thus, in order to connect the inner tube 60 and the outer tube 62 to their respective tubes, both ends of the inner tube 60 and the outer tube 62 should be expanded in their diameters sufficiently so as to be suitable to the diameters of the corresponding tubes.
However, since the inner tube 60 and the outer tube 62 are extruded integrally, it is not so easy to expand the diameters of the inner tube 60 and the outer tube 62. As a pair of connection points exists at both ends of the inner tube 60 and the outer tube 62, working ability deteriorates and the refrigerant leakage possibility increases.
To conserve energy and improve efficiency of the system, U.S. Pat. No. 5,243,837 (Radermacher) discloses a subcooling system for a refrigeration cycle of a multi-compartment refrigeration apparatus. In this apparatus, the heat exchange relationship can be effected by an internal subcooler in which nonazeotropic working fluid leaving the condenser is directed though a conduit within the tube of a fin-tube evaporator, the conduit being of smaller dimension than the tube of the evaporator. U.S. Pat. No. 5,406,805 (Radermacher) discloses a tandem refrigeration system which can reliably cool two or more compartments economically and efficiently. This is accomplished by operating the system with a single compressor, providing two evaporators in series, operating the evaporators at the same pressure level at any given time, and operating only one evaporator fan at a time. However, such systems still have the problem of working ability deterioration and of refrigerant leakage possibility as described above.